I. Kev txhais thiab kev faib tawm ntawm cov khoom siv hlau tsis ua haujlwm
Cov khoom siv hlau tsis ua haujlwm yog hais txog cov txheej txheem ntawm kev siv, vim muaj ntau yam, ua rau cov khoom siv hlau tsis tuaj yeem txuas ntxiv kom tau raws li nws cov qauv tsim lossis kev ua haujlwm ntawm lub xeev. Qhov kev ua tsis tiav no tuaj yeem tshwm sim los ntawm ntau yam, xws li degradation ntawm lub cev ntawm cov khoom, tshuaj corrosion, mechanical puas, thiab lwm yam.
pob txha: Raws li qhov loj ntawm cov khoom deformation, pob txha tuaj yeem muab faib ntxiv rau cov pob txha tawg thiab pob txha tawg. Cov pob txha tawg yuav muaj cov txheej txheem deformation tseem ceeb ua ntej qhov tshwm sim ntawm cov pob txha tawg tuaj yeem tshwm sim tam sim ntawd, tsis muaj qhov pom tseeb ntawm deformation, thiab yog li ua rau muaj kev puas tsuaj ntau dua. Feem ntau ntawm cov pob txha pob txha kuj muaj xws li qaug zog pob txha thiab cov pob txha pob txha zoo li qub, qhov uas qaug zog pob txha yog vim pob txha ntawm cov khoom nyob rau hauv lub caij nyoog kev nyuaj siab cycling kev khiav hauj lwm, thaum static load fracture tshwm sim nyob rau hauv static load.
Hnav thiab tsim kua muag:hnav thiab tsim kua muag yog vim yog castings nyob rau hauv high-speed, vibration, overload thiab lwm yam kev khiav hauj lwm tej yam kev mob, kev ua hauj lwm ntawm cov neeg kho tshuab deg kev sib txhuam ntawm ib leeg thiab ua rau cov khoom hnav thiab tsim kua muag, thiab ces ua rau cov khoom tsis ua hauj lwm. Kev hnav tuaj yeem muab faib ua ntau yam xws li hnav hnav, hnav hnav, qaug zog hnav, hnav corrosive lossis micromotion hnav. Hauv kev siv tshuab, abrasive hnav yog ib qho ntawm ntau hom kev hnav.
Corrosion:Corrosion yog ib qho tshuaj lom neeg lossis electrochemical cov tshuaj tiv thaiv uas tshwm sim thaum cov khoom siv hlau nkag mus rau hauv qhov nruab nrab ib puag ncig, ua rau txo qis hauv cov khoom siv lossis kev puas tsuaj. Corrosion tuaj yeem muab faib ua tag nrho cov corrosion thiab hauv zos corrosion, uas hauv zos corrosion ntau dua, nrog rau kev ntxhov siab corrosion, pore corrosion, intergranular corrosion thiab ntau lwm yam.
Kev ua tsis tiav ntawm cov khoom siv hlau yuav tsis tsuas yog txo cov khoom siv tau zoo, tab sis kuj tuaj yeem ua rau muaj kev hem thawj rau cov neeg ua haujlwm kev nyab xeeb. Yog li ntawd, tsis ua hauj lwm tsom xam ntawm cov ntaub ntawv hlau yog qhov tseem ceeb, uas tuaj yeem txheeb xyuas qhov ua rau tsis ua haujlwm thiab tawm tswv yim zoo los txhim kho qhov zoo thiab kev sib tw ntawm cov khoom.
II. Ua rau tsis ua haujlwm ntawm cov khoom siv hlau
1. Cov khoom siv sab hauv tsis zoo
Shrinkage thiab loosening
Txhais: Shrinkage yog cov hlau nyob rau hauv cov txheej txheem condensation vim ntim contraction nyob rau hauv lub ingot los yog casting plawv ntawm lub tsim ntawm tubular (los yog flared) los yog tawg qhov chaw. Kev xoob yog nyob rau hauv cov cua txias ceev, txawm hais tias kom tsis txhob muaj qhov shrinkage loj, tab sis cov kua hlau thiab cov khoom hlau ntawm qhov sib txawv ntawm qhov sib txawv tseem ua rau ntau qhov me me shrinkage qhov faib hauv cov hlau.
Cov teebmeem: Qhov tseem ceeb txo cov khoom siv kho tshuab ntawm cov khoom, tuaj yeem ua rau qaug zog ua rau tawg, thiab cuam tshuam rau corrosion kuj ntawm cov khoom.
kev cais
Txhais: qhov tshwm sim ntawm cov tshuaj tsis sib xws hauv cov castings, muab faib ua microscopic segregation (xws li intracrystalline segregation) thiab macroscopic segregation (xws li density segregation).
Kev cuam tshuam: ua rau kev ua haujlwm tsis sib xws ntawm cov castings, cov teeb meem loj yuav ua rau cov khoom seem.
suav nrog
Txhais: cov khoom siv hlau lossis cov khoom tsis yog xim hlau nrog lub ntsej muag meej nrog cov matrix. Raws li qhov xwm txheej yuav muab faib ua hlau inclusions thiab non-metallic inclusions.
Kev cuam tshuam: cuam tshuam rau cov khoom siv kho tshuab ntawm cov khoom, ua rau muaj kev pheej hmoo ntawm kev tawg.
npuas
Txhais: hlau nyob rau hauv lub xeev molten yuav yaj ib tug loj tus naj npawb ntawm gases, nyob rau hauv lub condensation txheej txheem vim txo solubility thiab tso tawm cov roj nyob rau hauv cov hlau sab hauv tsim ntawm gas npuas.
Cov teebmeem: Txo qhov ua tau zoo ntawm cov ntu ntu ntawm cov hlau casting, txo lub zog ntawm cov khoom thiab tej zaum yuav ua rau tawg.
Tsim kev puas tsuaj
Kev tsim qauv tsim tsis tsim nyog: xws li qhov muaj nyob ntawm qhov chaw muaj kev ntxhov siab nyob rau hauv qhov chaw thauj khoom, ua tsis tau zoo tsim ua rau tsis ua haujlwm.
Kev xaiv cov ntaub ntawv tsis raug: kev xaiv cov ntaub ntawv tsis tsim nyog, lossis kev nkag siab tsis txaus ntawm kev ua haujlwm ntawm cov khoom, ua rau cov khoom siv tsis tuaj yeem ua tau raws li cov kev xav tau.
Kev ua haujlwm tsis zoo
Kev kho cua sov tsis zoo
Xws li: quenching tawg, tempering tawg.
Kev cuam tshuam: txo lub zog thiab toughness ntawm cov khoom, ua rau muaj kev pheej hmoo ntawm pob txha.
Cold processing molding defects
Xws li: kev sib tsoo tsis xws luag, txiav tsis xws luag, txias taub hau tsis xws luag.
Kev cuam tshuam: cuam tshuam rau qhov zoo ntawm qhov chaw thiab qhov tseeb ntawm cov khoom, txo qhov kev ua tau zoo ntawm cov khoom.
Cov kev tsis zoo nyob rau hauv tus txheej txheem ntawm kev siv
Kev ntxhov siab ntau dhau: cov khoom raug cuam tshuam rau sab nraud ntau dhau ntawm kev siv, ua rau deformation lossis tawg.
Corrosion: cov ntaub ntawv nyob rau hauv cov av noo, kub kub, acid thiab alkali thiab lwm yam hnyav ib puag ncig corrosion, ua rau kev ua tau zoo degradation.
qaug zog: cov khoom nyob rau hauv qhov kev txiav txim ntawm alternating load, tom qab ib tug tej lub sij hawm ntawm qaug zog tawg.
Environmental yam
Kub: kub ib puag ncig yuav ua rau cov khoom oxidation, softening, txo nws lub zog thiab hardness.
Nruab nrab: ib puag ncig xov xwm tshwj xeeb tuaj yeem ua kom cov txheej txheem corrosion ntawm cov khoom.
Humidity: Cov av noo ntau dhau tuaj yeem ua rau cov ntaub ntawv nqus dej, ua rau o, warping, thiab kev loj hlob ntawm pwm lossis mildew. Qhov no tuaj yeem ua rau muaj kev puas tsuaj tshwj xeeb rau cov khoom siv hluav taws xob, qhov chaw noo noo tuaj yeem ua rau luv luv thiab puas tsuaj mus tas li.
Kev Tiv Thaiv UV: Ntev ntev raug rau ultraviolet (UV) hluav taws xob los ntawm tshav ntuj tuaj yeem degrade ntau cov ntaub ntawv, ua rau lawv nkig thiab poob lawv cov xim thiab cov qauv kev ntseeg. Qhov no tshwj xeeb tshaj yog rau cov yas, xim, thiab textiles.
Chemical Exposure: Kev sib cuag nrog cov tshuaj phem tuaj yeem ua rau muaj ntau yam kev tshwm sim, suav nrog kev tawg, tawg, thiab tshuaj lom neeg tawg ntawm cov khoom. Qhov no yog ib qho teeb meem tshwm sim nyob rau hauv cov chaw lag luam uas cov ntaub ntawv tuaj yeem cuam tshuam nrog cov kua qaub, cov hauv paus, cov kuab tshuaj, lossis lwm yam khoom siv.
